Filament bar casing



Jan. 11, 1955 s. l. WEISS FILAMENT BAR CASING Filed Aug. 8, 1952 Y INVENTOR hw'eylhfeas BY M Ang? EYs United States Patent O FILAMENT BAR CASING Shirley I. Weiss, New York, N. Y.

Application August 8, 1952, Serial No. 303,438

13 Claims. (Cl. 317-235) This invention relates to casings for filaments and more particularly to the casing for a filament bar of semi-conductive material.

As conducive to an understanding of the invention, it

i is noted that filaments for semi-conductive material such as germanium, when used, for example, in electronic equipment in place of vacuum tubes, must have leads connected thereto for connection into the circuit. As the filament, which generally is in the shape of a bar, is small in size and brittle, it is difficult to handle and is likely to break when the leads are connected thereto, and even if such leads should be connected without breakage of the filament, unless relative movement can be prevented between the leads and the filament, any slight vibration such as would occur in a vehicle or aircraft in which the unit Was mounted would cause breakage of the filament.

Where the semi-conductive material is connected to function as an amplifier, in addition to the connection of two leads to the ends of the filament bar, it is necessardy to connect a third lead at a point intermediate such en s.

As the sensitivity of the unit which is known commercially as a Transistor depends upon the particular 1ocation of the third lead, the latter must be moved from place to place, before it is permanently connected to the filament bar, until a particular location is determined which provides the best result.

Where the filament bar is not adequately sup orted While the third lead is p moved, the bar is also likely to break. In addition, once the optimum position of the third lead is found, it must be securely retained in such position Without likelihood of movement.

It is accordingly among the objects of the invention to provide a casing for a filament bar of semi-conductive material which will securely retain such bar in position n and provide support therefor along its entire length and which facilitates connection of terminal leads to the ends of the bar without likelihood of breaking thereof, which casing is also designed to facilitate the connection of a third lead to the filament between the ends thereof without likelihood of breaking of the filament even with repeated movement of such third lead to an optimum position against such filament and which facilitates fixing of such third lead in place without likelihood of derangement, which casing is neat, compact, light in weight and may readily be fabricated from low cost materials and which facilitates mass production assembly, with a minimum of breakage of the delicate filaments, of a complete electrical unit which can withstand severe shock and vibration without derangement.

According to the invention, the filament bar casing desirably comprises an elongated cup-shaped housing in which is positioned a filament holder corresponding in dimensions to the inside dimensions of the housing. The filament holder desirably has a pair of terminal leads molded in each end thereof and extending therethrough, said holder, between said leads, having an elongated slot of greater cross section on the outer side of the holder than on the inner side thereof. A filament bar of semiconductive material conforming to the length of the slot is positioned in the enlarged portion thereof and the terminal leads are electrically connected by suitable conducting solder to the adjacent ends of the filament bar and desirably extend outwardly from the housing.

According to one embodiment of the invention, a nar-` ICC row strip is provided which defines a mount for a contact wire or cat Whisker, which is affixed to one side of the mount and is electrically connected to a terminal lead extending from the other side of the mount. The mount is of such length as to extend transversely across the side edges of the cup-shaped housing with the cat Whisker extending through the narrow portion of the slot in the lilament holder and being in engagement with the filament bar. The mount is securely retained in fixed position by means of a suitable insulating cement which fills the cup-shaped housing and which securely retains the three terminal leads in fixed position Without likelihood of displacement.

In the accompanying drawings in which are shown one or more of various possible embodiments of the several features of the invention,

Fig. l is a perspective View of the transistor unit,

Fig. 2 is a longitudinal sectional view thereof on a greatly enlarged scale taken along line 2-2 of Fig. l,

Fig. 3 is a transverse sectional view 'thereof also on a greatly enlarged scale taken along line 3 3 of Fig. l, and

Fig. 4 is an exploded perspective view thereof also on a greatly enlarged scale.

Referring now to the drawings, the filament bar casing desirably comprises a substantially rectangular cup-shaped housing 11 illustratively of greater length than width and preferably formed of suitable insulating material such as Bakelite, polystyrene or the like. Desirably, the side walls 12 and end walls 13 of the housing taper inwardly toward the floor 14 thereof from the rim 15 of the mouth of the housing.

Positioned in the housing 11 is a filament bar holder 18 which also desirably is rectangular in shape, of greater length than width and has tapering end and side walls 19 and 21 respectively, which conform to the configuration of the inner wall of the housing, the dimensions of the holder being such that when it is positioned in the housing adjacent the floor 14 thereof, as shown in Figs. 2 and 3, it will tit snugly in place. The holder 18 desirably has a pair of terminal leads 22 and 23 molded therein near each end thereof and protruding beyond both faces 24 and 25 of the holder, the protruding ends 26 gf the leads 22 and 23 extending but slightly beyond the ace 24.

The holder 18 desirably has a longitudinal slot 29 therethrough extending between the terminal leads 22 and 23. The slot 29 is desirably of greater Width as at 31 at the portion thereof adjacent the face 24 than at the portion 32 thereof adjacent the face 25. Positioned in the enlarged portion 31 of slot 29 is a filament bar 33 of semi-conductive material such as germanium. The bar 33 which extends substantially the entire length of slot 29 is affixed at its ends to the adjacent protruding ends 26 of terminal leads 22 and 23 respectively by a suitable conducting solder 34 such as colloidal silver. The assembled filament holder, including the filament bar 33, is securely retained in the housing adjacent the floor 14 thereof by a non-conductive cement 35 such as a polystyrene cement.

Means are desirably provided to connect a third terminal lead 38 to the filament bar 33 intermediate its ends. For this purpose a rectangular strip or mount 39 is provided, preferably of metal, of length substantially equal to the Width of the housing. The strip 39 desirably has its ends 41 bent to define lateral wings which rest on the side rims 15 of the housing as shown in Fig. 3 so that when the central portion 43 of the strip extends slightly into the mouth thereof, transverse movement of the mount is restrained, but longitudinal movement thereof is afforded. The strip 39 desirably has a contact wire preferably a cat Whisker 42, affixed as by soldering to the inwardly bent portion 43 thereof and the terminal lead 38 is also afiixed as by soldering the opposed surface of said strip 39. The cat Whisker 42 is of such length that when the lateral wings 41 of mount 39 are positioned on the side rims 15 of the housing 11, the cat Whisker 42 will extend through the reduced portion 32 of slot 29 and `contact the filament bar 33. The mount 39 may be moved along the side rims 15 until the cat Whisker engages shown).

Afterthe optimum location of the cat Whisker 42`has been determined, the mount 39 is securely affixed in place by means of a non-conductive cement 35 suchas polystyrene which is placed in the concavity of the housing 11 to fill the latter and will also enter the narrow portion 32 of the slot 29, the cement securely `bonding to the housing and to the filament holder thereby securely retaining the mount in position and also retaining .the

terminalleads in fixed position with respect to each other without likelihood of displacement.

With the construction above described, a small, compact casing for a filament bar is provided to form a com.- plete transistor unitwhich functionsin the manner similar to a conventional triode vacuum tube. By reason of the support for the terminal leads 22, 23 and S3, afforded by the'holder 18 and by the cement 35, there is no likelihood of relative movement between the filament bar 33, the conducting leads 22, 23 and 38 and the contact mount 39. As a result, the transistor can withstand Ysevere vibration or shock as would occur in a movingvehicle, an airplane or a projectile.

By reason of the compactness of the unit, a large number may be positioned in a relatively small space yand even if in engagement with each other, by reason of the rigid construction thereof above described, no derangement of the elements ofthe units would occur evenif adjacent units should be jarred against each other.

As many changes could be made in the above construction, and many apparently Widely different embodiments of this invention could be made without departing from the scope of the claims, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

Having thus described my invention, what I claim-as new and desire to secure by Letters Patent of the United States is:

1. A casing for a filament bar of semi-conductive material comprising a cup-shaped housing, a holder in said housing having an elongated slot therein, a filament bar in such slot, and a pair of terminal leads affixed in said holder near each end thereof and extending outwardly therefrom for connection at one end respectively yto the ends of such filament bar.

2. The combination set forth in claim 1 in which an insulatingV cement in said housing rsecurely retains said holder therein and securely retains said terminal leads in spaced relationship and prevents relative movement between said leads, said holder and said casing.

3. A casing for a filament bar of semi-conductive material, comprising a cup-shaped housing, a'holder in said housing conforming to the inside dimensions adjacent the floor thereof and fitting snugly therein, said holderhaving an elongated slot therein, a filament bar in such slot, and a pair of terminal leads affixed in said holder near each end thereof and extending outwardly therefrom for connection to the ends of such filament bar.

4. A casing for a filament bar of semi-conductive material comprising a substantially cup-shaped housing of greater length than width, the walls of said housing tapering inwardly 'from the rim of the mouth thereof to the floor of said housing, a substantially rectangular'holder `of insulating material in said housing of greater length than width, having its walls tapering inwardly to conform to the inside dimensions of the walls of the housing adjacent the floor thereof for snug fit of said holder in said housing, said holder having an eiongated slot therein, a filament bar in such slot, and a pair of terminal leads affixed in said holder near each end thereof and extending outwardly therefrom for connection at one end respectively to the ends of such filament bar.

5. The combination set forth in claim 1 in which the ends of the terminal leads are connected by colloidal silver to the ends of the filament bar respectively.

6. A casing for a filamentbar of semi-conductive material comprising a cup-shaped housing, a holder in said housing having an elongated slot therethrough, a filament `bar-inl suchslot, a pair-of terminal leads affixed-in said holder near each end thereof for connection at one end respectively to the ends of such filament bar, a third terminal lead, and means extending through said elongated slot connecting said third terminal lead to such filament bar.

7. The combination 'setforth in claim 6 in which the means extending through said slot comprises a contact wire electrically connected at one end to said third terminal lead, and means securely to retain said contact wire in fixed position against such filament bar.

8. The-,combination set forth in claim 6 in which the slot in said holder is of greater cross section on the inner side thereof adjacent the floor of said housing than on the outer side thereof, and the filament bar is positioned in said greater cross sectional portion of said slot.

9. The combination set forth in claim 6 in which a strip lextends across the'mouth of said casing, said conends of such filament bar, said leads extending outwardly yfrom said housing, ka strip extending transversely across the rim ofthe mouth of said housing, a contact wire -afhxed' at one end to said strip on one side thereof and .extending through said .slot for engagement with such filament bar and a third terminal lead afxed to the other `side of said strip, `electrically connected to said contact ywire'and extending outwardly from said housing.

11. The .combination set vforth in claim 10 in which said Vstrip .has an inwardly bent portion extendinginto the mouth of said housing and lateral wings resting on the side rims ythereof thereby preventing lateral displacement of said strip, ybut permitting longitudinal movement Vthereof,;said contact wirebeing affixed to the inner face V'of said inwardly bent portion and said terminal lead to the outergface thereof.

1.2. The combination set'forth in claim 11 in which aninsulatlng cement in said housing securely retains said 'holder therein and securely retains-said strip, said contact wire and said terminal leads in fixed position with respect toeach other.

13. A transistor comprising a substantially cup-shaped housing of greater length than width, a holder of insulating-material in said housing conforming to the dimensions thereof and having an elongated slot therethrough ofgreater cross section on the inner side thereof adjacent the floor of the housing than on the outer side thereof, -agfilament bar of semi-conductive material in said larger cross 'sectional portion of said slot, a pair of terminal `leads ,affixed in said holder near each end thereof for rconnection at one endjrespectively to the ends of said filament bar, said leads extending outwardly from said ,hous1ng, a `strip extending transversely across the rim of the mouth of vsaid housing, a contact wire affixed at one end to said strip on one side thereof and extending through the narrow portion of said slot into engagement with said filament bar, a third terminal lead affixed to the other side of said strip electrically connected to said contact wire `and extending outwardly from said housing and means securely to retain said holder in said housing and securely retaining said strip, said contact wire and vsaid terminal leads in fixed position withrespect to each other.

References Cited in the tile of this patent UNITED STATES PATENTS 2,000,642 Lamb Ma 7 1935 2,526,207 Donieyet ai. cedri, 195o 2,561,411 Pfann July 24, 1951 2,629,802 Pantchechnikoff Feb. 24, 1953 

